Mountain Bike Buying Guide

Worry not however, for we’ve put together this extensive buyer’s guide to help you find your perfect mountain bike – one that’ll conquer both the steep climbs and dicey descents. From off-road geometries to wheel sizes, we’ve got it all covered right here, making sure that your final decision is the right decision…

Mountain bikes have a wealth of other features too, but these can differ depending on which type of mountain bike you choose. Each type of mountain bike is optimised for the specific terrain that it’s built to ride on. Here are the three main types of mountain bike:

Trail Mountain Bikes

Trail bikes are designed for flying down the descents and gliding up the climbs with an unparalleled level of both speed and confidence – perfect for technical singletrack riding.

They’re often kitted out with both front and rear suspension, giving you the ability to send it down fast and technical descents. They’re also lightweight and stiff, especially if they have a built-in suspension lock feature. This reduces the amount the suspension compresses so that more of the power being put in to the pedals transfers to the wheels. This amount of control means they can clamber up the climbs almost as quickly as they can hurtle down the other side.

Geometry and frame design is another important feature of a trail bike. The best trail bikes have just the right amount of slackness in their head angle to inspire confidence on the descents, but not too much that it starts to make the handling feel slow and unresponsive. Trail bikes have a wide variety of wheel sizes to choose from, but the most popular are 27.5” and 29” wheels, the benefits of which will be discussed later in this guide.

Cross Country (XC) Mountain Bikes

When it comes to speed and pedalling efficiency on off-road terrain, you can’t quite beat an XC mountain bike. With their lightweight builds, aggressive angles and big 29” wheels that help you carry speed over a wide variety of surfaces, these bikes are some of the best for racing off-road.

XC bikes are often hardtails, with suspension located solely in the front-end of the bike. This means that you won’t be hitting any big jumps on one of these bikes, nor shredding technical downhills, but that’s not what these bikes are designed for. With a rigid back end, these bikes are a lot stiffer, meaning you can push a lot more power through the pedals. That being said, an XC bike with rear suspension is a good middle ground between a trail bike and an all out XC race bike, a combination of speed and agillity plus trail taming prowess.

They’re also incredibly efficient, allowing you to ride hard for a whole lot longer, covering a large amount of ground at speed. 29” wheels are a popular choice for most XC bikes, but some do sport 27.5” wheels. Once you’ve read up on the pros and cons of each later in the guide, you can make this important decision.

Enduro/Downhill Mountain Bikes

These bikes are designed for shredding gnarly descents at hair-raising speeds, channelling a super-slack frame design, wide wheelbase and long reach to help you descend as fast as possible. They’re built to race, especially downhill bikes which are optimised for flying downhill and nothing else – you won’t be winning any uphill sprints on one of these bikes.

Enduro bikes are a little different. They’re designed to excel in the Enduro race discipline, a type of mountain biking that combines climbs and timed descents into one fast-paced event. Both are built with descending in mind however and each will sport a massive amount of suspension in the fork, frame and rear end to soak up and absorb all of the high-impact hits.

The wheel size debate is a big one when it comes to Enduro and Downhill bikes, but the majority of riders – including the sport’s top professionals – choose to ride 27.5” wheels most often.

Steel frames are best known for their comfort and durability. Steel is extremely compliant and so soaks up a lot of buzz and chatter from the trail underneath, making for a more comfortable ride. It is heavy however, bad news for those of you wanting to fly up steep, off-road inclines.

Aluminium is the most common frame material in the mountain biking world, largely thanks to its all-round performance qualities. It’s lightweight, stiff yet compliant, durable and power efficient, making it perfect for any kind of mountain bike. There are many different kinds of aluminium out there, which differ in both price and performance, giving you plenty of choice.

For the lightest and stiffest material however look no further than carbon fibre. This material is a relatively modern introduction to the world of mountain biking, but it has well and truly took off, the material offering the best performance qualities out of the three most popular frame materials. It’s a lot more expensive than aluminium, but if you’re planning on winning any races, this is a price you’ll be willing to pay.

Finding The Perfect Size And Geometry

Finding a bike that fits you is crucially important–not only will it help you ride more comfortably, it’ll also help to deliver power to the pedals more efficiently. We have a rough size guide here to help make this an easy process, however, this is just an example and the guide will vary on model.

Geometry is a little different to fit and something that you might just want to take into account before choosing a certain size. Different frame geometries can change the size somewhat, so make sure you familiarise yourself with this example of one of our geometry charts here.

A mountain bike’s geometry is perhaps the most important aspect of its whole design, the geometry dictating the overall handling and feel of the bike. Geometry can differ massively between different brands and models of bikes – here are some of the measurements to look out for:

1. Seat angle

The angle of the seat tube relative to the ground.

A steeper angled seat tube will put the saddle directly over the bottom bracket, making pedalling easier and more efficient. This also helps with climbing, pushing your weight forwards to make sure your front wheel doesn’t lift up.

An angle around the mid-70s is best.

2. ‘Effective’ top tube length

The ‘effective’ length from the top of the head tube to the seatpost, measured horizontally.

This measurement provides a better idea of how roomy a bike will feel, compared to just simply measuring the length of the top tube. It factors in stem length and the offset of the saddle to help give you an idea of how the bike will feel once you’re sat in the saddle.

3. Head angle

The angle (measured from horizontal) of the steerer tube of the fork.

Head angles massively influence steering and overall handling. Slacker angles slow down a bike’s steering response, but make descending a little easier. Steeper angles make the handling feel more responsive and nippier on flat terrain.

Bikes that are built for flying downhill benefit, therefore, from slacker angles in the low 60s. Whereas XC bikes, designed for charging over off-road rolling terrain, benefit from steeper head angles in the high 60s.

4. Down tube length

The distance from the centre of the bottom bracket to the centre of the bottom of the head tube.

Like the ‘effective’ top tube length, the down tube length provides an indication of how roomy the bike will feel once you’re sat in the saddle – it’s just a lot easier to measure. It’s also a great tool for working out a bike’s true size and whether it will fit you. 

5. Wheelbase

The horizontal distance between the front and rear axles.

The longer the wheelbase, the more stable your bike will feel. This comes at a cost however, as the longer the wheelbase, the greater your steering angle – meaning it’ll be a lot harder to skirt around tight corners on a bike with a long wheelbase.

6. Bottom bracket height

The vertical distance from the floor to the centre of the bottom bracket.

Lower bottom brackets improve stability and make the bike feel a lot more agile when turning. This is because it lowers the rider’s centre of mass, giving the bike a more planted feel. The disadvantage of a low bottom bracket, however, is that it increases the chance of bashing the pedals or chainrings on the ground, so keep this in mind.

Hardtail Or Full Suspension

The type of off-road riding you’re planning on doing is going to massively influence your suspension choice.

Hardtails

These bikes have a rigid back end, making them a lot stiffer and more powerful over rolling trails – this is why most XC bikes are hardtails.

They have suspension solely in the front, which helps to absorb most of the buzz from the trails, but will still get hit hard by really rocky stuff. With only one suspension system, a hardtail bike is often lighter than a full suspension rig, making it the bike of choice for those looking to race over variable terrain.

Full suspension

These bikes have suspension in both the front and rear end of the bikes, offering increased comfort and control over rough and gnarly trails.

They’re more suited to technically demanding terrain, particularly downhills which require a large amount of suspension just to absorb all the big hits and jumps. They may be a little more complicated than hardtails, and therefore harder to maintain, but they do offer significant performance advantages on the more technical trails.

Wheel Size

Mountain bikes, up until the late 90s, were fitted with 26” wheels as standard. It’s only in the last few decades that larger wheels have started to be introduced.

The largest wheel size, 29” wheels, are the same size as your standard 700c wheels on a road bike. These wheels roll over obstacles a lot more easily than smaller wheels, and so carry a lot more speed – making them perfect for racing.

29” wheels also provide better traction thanks to the larger tyre footprint, meaning you can clamber up slippy inclines a lot easier. They are slightly heavier however, and a bit less responsive than smaller sized wheels.

In between 26” and 29” wheels are 27.5” wheels, the half-way-house option for those that want the faster rolling abilities of a 29”, but the snappier handling of a 26”. These 27.5” (sometimes referred to as 650b) wheels are the new standard on most mountain bikes as they offer a good balance between speed and control making them perfect for both beginners and experienced shredders alike.

Drivetrain And Brakes

Most mountain bikes come with a one-by system nowadays, with a varying number of gears on the rear cassette – anything from 12-speed to 8-speed. Unlike on a road bike you don’t need a massive number of gears to excel on off-road terrain, and a one-by system provides more than enough gears to help you glide up steep climbs and fly down the other side.

However, there are some riders that like the feel and wider range of a double chainring drivetrain, especially cross-country riders. The wider range of gears suits this discipline more than others, allowing the bike to be ridden at high speed on both flat tarmac sections and on long, muddy climbs.

When it comes to brakes, almost every modern mountain bike now comes with disc brakes. Discs provide more powerful and more reliable braking abilities compared to rim brakes, making them far superior for use off-road.

Which kind of disc brakes you go for, however, is up to you. Mechanical disc brakes are often cheaper and easier to maintain, but they’re not quite as good when it comes to stopping power. Hydraulic discs, on the other hand, are extremely powerful but are much more difficult to maintain and are often much more expensive.

Do your research

Spending time researching your mountain bikechoices is half of the fun when it comes to buying a new bike. Pitting bikes against one another will help you to find the one that’s most suited to your riding style. It’ll also helpyou to decide which features and components you want on your bike, and which ones you don’t.

The more time you spend deliberating, the more informed a decision you’re going to make. Finding the ideal mountain bike doesn’t happen overnight, but with this extensive buyer’s guide at your disposal, it won’t be long now until you discover your perfect bike.Happy riding.

Be sure to take a look at our wide range of mountain bikes.There’s definitely one there with your name onit!